Another explanatory possibility to be considered is that mutual intercellular signaling analogous to Delta/Notch signaling may contribute to these early differentiative steps, so that, e.g., differentiating Trh cells cause surrounding postmitotic neurons to become Ghrh cells, or vice versa.
The Tree based model is more efficient in dealing with missing values and given that the two approaches identify a nearly identical subset of useful explanatory variables, the possibility that the missing values are having an undue influence on the final regression model is remote.
We control for this possibility by explicitly considering all possible explanatory eQTL in the full sequence data available for our replication sample.
Motivated by the results of the regression analysis, we investigated the impact of the explanatory variables for the possibility to identify candidate loci for selective sweeps.
Although a number of factors were shown to affect sickness certification, we cannot exclude the possibility that other explanatory factors may have been involved which were not studied here.
It also raises other interesting questions concerning such matters as the explanatory relevance of content and the possibility of a priori self-knowledge.
Does it offer the possibility of comparing the explanatory value of alternative theories?
We considered the possibility of interaction between some explanatory variables and sex, because of the marked sex differences in their distribution and introduced interaction parameters into the regression models to test for interaction formally using the likelihood ratio test.
Second, Dr. Doolittle raises the possibility that biology has no overarching unifying theory, and that a mature explanatory toolkit is the apex of biology.
